I think it looks a little stiff, and the R is off a little.
The "R" is a little unusual but I have seen similar ones before. The rest of the autograph looks good to me but of course only my opinion.
Ruth is tough now, in light of the "questionable" balls that were authenticated by JSA and PSA a few years ago. its tough to find good, reliable reference points. Here is one that I believe to be authentic. Rather than looking at each letter technically, I look at the overall signature and the one in question just seems to lack the "bounciness" and feel of an authentic Ruth. but like Randy says, its just an opinion.